1. Field of the Invention
The present invention relates to a coupling device for use with a fuel injector and, more particularly, to a coupling device (connector bridge) used to connect solenoid wires to an end cap assembly while maintaining the solenoid wires away from a control valve of the fuel injector.
2. Background Description
Many internal combustion engines are designed to use fuel injectors. In such a typical internal combustion engine, the fuel injector is mounted partly within the combustion chamber of the engine, with the control valve mechanism mounted beneath the valve covers of the engine. In this type of configuration, the control valve mechanism which, in some conventional injectors, include solenoids and end caps, are connected to an engine wire harness assembly via solenoid wires. The engine wire harness, in turn, is connected to a driver which provides or delivers a current to the solenoids for providing control to the fuel injector, itself.
In general, the driver delivers a current or voltage to an open side of an open coil solenoid via the solenoid wires. The magnetic force generated in the open coil solenoid will shift a spool into the open position so as to align grooves or orifices (hereinafter referred to as “grooves”) of the control valve body and the spool. The alignment of the grooves permits the working fluid (i.e., hydraulic fluid) to flow into an intensifier chamber from an inlet portion of the control valve body. The high-pressure fluid then acts on an intensifier piston which, in turn, compresses fuel located within a high-pressure plunger chamber. As the pressure in the high-pressure plunger chamber increases, the fuel pressure rises above a needle check valve opening pressure. At the prescribed fuel pressure level, the needle check valve will shift against a needle spring and open the injection holes in a nozzle tip for injection.
At the end of the cycle, the driver will deliver a current or voltage to the closed coil solenoid. The magnetic force generated in the closed coil solenoid will shift the spool into the closed position so as to align grooves of the spool with ejection or discharge ports of the control valve body. This alignment permits the working fluid to flow from the intensifier chamber, through the discharge ports and then be ejected from the control valve body, via the discharge ports. The discharge of the working fluid is at a high pressure. Once the working fluid is discharged, it is captured and reused by the injector. Of course, fuel injectors may vary in their functionality such as fuel injectors with needle back pressure systems and the like; however, the above description is generally descriptive of the basic functioning of the fuel injector.
In these types of systems, however, the solenoid wires are permanently connected to the end caps and are routed over the discharge ports and adjacent the rocker arm assemblies of the engine. The wire harness assemblies for the solenoid wires are also located adjacent the rocker arm assemblies in such a manner that the solenoid wires must bridge the gap between the open and closed coil solenoid and the wire harness assembly (which is approximately 150 mm). In such a harsh environment, the solenoid wires are subject to failure, from such causes as:                1. vibrations caused by the rocker arm assemblies,        2. chaffing or striking from the rocker arm assemblies, or        3. vibrations caused when the working fluid is discharged from the fuel injectors.These factors, over time, lead to a failure of the fuel injector. This, of course, adversely affects the efficiency of the engine and, in instances, may result in a catastrophic failure of the engine. To repair the engine, or more particularly the solenoid wires, the entire fuel injector must be replaced including the solenoid wires. This is due to the permanent connection between the solenoid wires and the end caps. Alternatively, the entire fuel injector must be removed from the engine and the solenoid wires replaced. This is a time consuming and costly process. It is also noted that the fuel injector and solenoid wire assembly (due to the one-piece assembly) may be difficult to maneuver into place, again leading to higher manufacturing and repair costs.        
The present invention is directed to overcoming one or more of the problems as set forth above.